back of the envelope, page-9

247247,
There is no perfect methodology of valuations of companies, perhaps more appropriate methods for particular type industries. When cashflow is highly variable DCF method is more appropriate.
Using your logic of a PE valuation of 5 would make no sense if only say 3 or 4 years of production left (not saying this is the case).
I have studied securities analysis at post graduate level & have over 40 years of successful investing experience & do it full time for a living, so I don't need to google DCF.
Perhaps it may be worth running a DCF on ITC then you will have a better understanding of how DCF work & a better knowledge of ITC. DCF knowledge is very good to have, but as your google response pointed out it is still dependant on reliable inputs.
Regards
Buffett